Effects of repeated retrieval on keyword mediator use: shifting to direct retrieval predicts better learning outcomes.

Keyword mediators are an effective memory technique to encode novel vocabulary: learners link a novel word form to its meaning with a mental image that includes a keyword that resembles the word form (e.g.,nyanya = tomato;keyword mnemonic:theninjachops thetomatoin half). Prior research suggests that such mediated form-meaning associations become less dependent on keywords after retrieval practice. The present study investigated if retrieval-induced decreases in mediator use predict word retention. Thirty participants learned novel vocabulary using experimenter-provided keywords and repeatedly retrieved the words from memory while thinking aloud. As expected, keyword use decreased with practice: learners stopped mentioning keywords for 21.6% of the words (on average after 8.27 retrievals). Shifting to direct, unmediated retrieval predicted higher form and meaning recall on a retention test after 6-8 days. Continuing retrieval practice until a shift has occurred to direct retrieval thus seems beneficial for retention.